US2425012A

US2425012A - Impact drill

Info

Publication number: US2425012A
Application number: US527179A
Authority: US
Inventors: Robert E Snyder
Original assignee: SNYDER OIL TOOL CORP
Current assignee: SNYDER OIL TOOL Corp
Priority date: 1944-03-20
Filing date: 1944-03-20
Publication date: 1947-08-05
Anticipated expiration: 1964-08-05

Description

R. E. SNYDER Aug. 5, 1947.

IMPACT DRILL Filed Marbh 2o, 1944 4 Sheets-Sheet 1 IN VEN TOR. P05522' E. SAQ/05e, BY

// awa Aug. 5, 1947. R. E. sNYDER 2,425,012

IMPACT DRILL Filed March 20, 1944 4 Sheets-Sheet 2 R. E. SNYDER Aug. 5, 1947.

IMPACT DRILL Filed March 20, 1944 0 l u If- .V80

4 Sheets-Sheet 3 INVENToR. @0.95275 .5M/05e,

Armen/5x R. E. SNYDER Aug. 5, 1947.

IMPACT DRILL 4 Sheets-Sheet 4 Filed March 20, 1944 INVENTOR. P05507 E. .5A/mee,

Arrow/ven Patented ug.'5, 1947 IIWPACT DRILL Robert E. Snyder, Pasadena, Calif., assigner to Snyder Oil Tool Corporation, a corporationof California Application Maren zo, 1944, serial No. 527,119

(ci. ass-zr) 34 Claims.

My invention relates generally to the art of earth boring, and more particularly to apparatus suitable for drilling deep wells by the rotary method. This present application is a consolidation and continuation in part of each of my copending applications Serial No. 388,627 and Serial No. 388,628, both filed on April 15, 1941, and includes only the apparatus disclosures and claims of each of said former cases; and the methods of using mud in drilling and controlling drilling shown in said former cases together with certain new matter .are the subject matter of my copending application, Serial No. 528,095, filed March 25, 1945.

One of the objects of my invention is to provide means for periodically imparting shock or impact to a drill bit while it is being continuously rotated against the formation being drilled.

Another object of my invention is the provision of means for imparting impact to a rotary drill bit, which means is at all times under the direct control of the driller operating the equipment from his station on the derrick oor.

A further object of my invention is to provide impacting means which is actuated by the engagement of an element thereof with the drilling iiuid within which the tool operates and does not depend for its operation upon contact with the walls or bottom of the hole being drilled.

Another object of my invention is to provide means actuated solelyv by contact with the drilling fluid for imparting impact to a rotary bit, wherein the duid-engaging means is of such nature that the rate of impacting is both a. function of the resistivity of the fluid and of the speed at which the drill is operated. In a modied form of my invention the iiuid engaging means is such that the rate of impacting is also a function of the rate of circulation of the drilling fluid.

A furtherobject is vtoimprove upon drilling apparatus of this general nature -by effecting a reduction in the number and complexity of the constituent parts thereof, thereby reducing the cost of production and operation of the apparatus without any impairment of operating efciency.

My invention possesses other objects and advantages, some of which with those enumerated will be set forth in the following description of various embodiments i my invention which are illustrated in the drawings accompanying and forming a part of the specification. It is understood that I do not limit myself to the showing made by the drawings and description as I mayv of that portion of the drill of Fig. 1 which serves' to generate the percussion or impact. The plane of section is indicated by the line 2-2 of Fig. l, and portions of the ligure are broken away to reduce its size,

Fig. 3 in a detail view in perspective of the impact generating cams and the actuating means therefor. Portions of the ligure are broken away and shown in section,

Fig. 4 is a side elevational view similar to Fig. 1 but showing a slightly modied form of impact drill. Portions of the ligure are broken away to reduce its length, y

Fig. 5 is a longitudinal sectional view of the modied form shown in Fig. 4,

Fig. 6 is a detail view in side elevation partly broken away of an impact drill employing a modied form of fluid-engaging blade,

Fig. 7 is a view similar to Fig. 6, showing a still further form of fluid-engaging means,

Fig. 8 is a view in side elevation of another form of impact drill embodying the principles of of the present invention, and shown in operative relation within a well being drilled. Portions of the figure are broken away and shown in section the better to reveal the interior construction,

Fig. 9 is va view in longitudinal section of the Adrill of Fig. 8,

Fig. l0 is a horizontal sectional view taken `on the line |0--I 0 of Fig. 9,

Fig. 11 is a horizontal sectional view similar to Fig. 10 but taken on the line II-II of Fig. 9,

Fig. 12 is a view in side elevation of another fiorlii dof my invention, shown in a Well being rl e Fig. 13 is a longitudinal sectional view oi' the form shown in Fig. 12,

Fis. 14 is a horizontal section view taken on the line l4-I4 of Fig. 12. and

Fig. 15 is a horizontal section taken on the line IS--IB of Fig. 13.

3 the lower end of a drill stem and rotated thereby after being lowered into a well. In order to expedite the drilling operation, the device of the present invention relies, in addition to the customary rotary motion of the bit at the lower end of the tool against the formation being drilled, upon impact or -percussive action directed against the formation by the drill inV a downwardly direction. The means for generating this impact preferably include a pair of opposed cooperating cams, one of which is connected to the drill to rotate therewith at all times, and the other of which is connected to an impeller carrying one or more vanes or blades which project into the circulation iluid which, being of a relatively thick or viscous nature, retards rotation of the impeller and the cam associated therewith, thereby developing a rotationaldierential of one cam with respect to the other which is necessary to cause them to override each other. The camsV are urged toward each other by suitable means, such as by a spring or by gravity, with the result that as this overriding action occurs,

the cams will come together with an appreciable shock or impact, thereby imparting a downward impact tothe drill which materially increases its drilling efficiency. The impact-actuating means has sufllcient clearance to avoid all contact with any part of the drilled hole walls or bottom, and is caused to operate solely by its engagement with iluid and fluid borne material in the drilled hole.

More specifically described and referring first to that modification of my invention which is illustrated in-Figs. 1, 2 and 3, the impact drill of the present invention comprisesa shank I| provided at its upper end with a threaded sub I2 or other suitable means of attachment to the lower end of a conventional drill stem I3. To

39 and carries a plurality of vanes or blades 31 extending radially outwardly from the body 36. The blades 31, however, are relatively short in their radial extent, being proportioned so that they extend only part way from the body 36 to the wall 38 of' the hole within which the tool is operating. It is apparent therefore -that the facilitatemounting a drill bit thereupon, an op.

, by circulation :uuid I9 forced downward through the bore of the drill stem |3 and the bore 2| of the shank by a pump 22 can escape into the hole being drilled adjacent the cutting edges 23 of the bit, whence the fluid I9 flows upwardly through the hole to the sump 24 provided at the top of the hole, carrying with it the detritus cut away from the formation being drilled.

Aiiixed rigidly upon the upper surface of he is a lower cam28 having one or more shoulders 29 on its upper surface. Disposed in cooperative relation above the lower cam 28 and rotatably mounted upon the shank |I is an upper cam 3|, the lower surface of which is provided with a shoulder or shoulders 33 corresponding and complementary to those on the lower cam 28. In addition to being rotatable upon the shank I I, the upper cam 3| is reciprocable thereon and is continually urged downwards by its own weight to frictional engagement with lower cam 28.

Carried by the upper cam 3| is a tubular body 36 which in the present modification is of such length that it extends upward for a material distance beyond the upper end of the shank and into telescopic relation with the lower end of the drill stem I3. The tubular body 36 is provided with a suitable number of breather holes head |4 and encircling the lower end of the shank only medium engaged by the blades 31 during the operation of the tool is the circulation fluid I9 and the material it carries.

This circulation fluid is conventionally of a relatively heavy nature, usually being composed of specially selected muds and/or chemicals appropriate to the particular drilling conditions. Moreover, the'circulation `fluid carries a relatively largeproportionate content 0f solid particles, inasmuch as one of its principal functions is to carry the detritus away from the drill as it is formed. Accordingly, the circulation uid will always be of a relatively thick, or viscous nature and will offer a certain amount of resistance to movement of the blades 31 therethrough. An important feature of my invention is that the extent to such resistance is not a constant' factor, but varies with the speed of rotation of the blades 31 therethrough as well as with variations in the characteristics of the fluid which determine the resistance which it offers to rotation of an impeller blade through the fluid.

Inasmuch as the blades 31 are carried by the tubular body 36 which is in turn affixed to the upper, cam 3|, it is apparent that the normal rotation of the upper cam 3| by reason of its frictional engagement with cam 28 will be retarded because of the engagement of the blades 31 with the circulating fluid I3.

Because of the sloping nature of the interengaging surfaces of the cams, the upper cam 3| and the tubular body 33 Will be lifted when the drill is rotated clockwise as indicated in the drawings, and this axial movement continues until the shoulder 32 of the cam 3| passes the shoulder 23 of the cam 28, whereupon the upper cam 3| and the tubular body 36 will drop sharply due to its own weight. This downward motion of the upper cam 3| and tubular 'body 36 is sharply arrested when the cams come together again, thereby imparting a shock or impact to the lower cam and through it to the drill bit l1. The percussion thus imparted to a rotating bit has beenit found to increase the drilling efiiciency of the bit to a very appreciable degree.

It becomes apparent, therefore, that if drilling I i conditions are such that the operator desires the drill bit to rotate without any impact action,

he can accomplish this by reducing the speed of rotation until the resistance to rotation of the tubular body and its associated cam is equal to or less than that of the frictional interengagement between the two cams which urges the upper cam and tubular body to rotate. 40n the other hand, if drilling conditions are such that the development of percussive action is desirable, the operator has merely to increase the speed of rotation of the drill Stem until the resistance to rotation of the upper cam which is offered by impingement of the circulation fluid against the vanes 31'is greater than the frictional interengagement between the cam faces. When these conditions obtain the tubular body 36 will lag, i. e. will not rotate 'as fast as the portions of the tool which are rigidly connected to the drill stem, thus causing the upper cam 3| to lag with respect to the lower ca m 28, thereby developing the desirable impact action.

It is apparent therefore that the impact action can be controlled in either of two ways: namely, (1) by keeping the fluid resistance constant and varying the speed of rotation of the drill in the iluid, or (2) by keeping the speed of rotation of the drill constant and varying the resistivity or viscosity of the fluid. It is further evident that the critical speed at which the impact action occurs is a function of the resistivity of the uid to the movement of the blades therethrough, i. e. the greater that resistivity, the lower the drill stem R. P. M, at which the impact means will begin to operate.

In this connection, it should be observed that the expression resistivity of the circulation iluid, is concerned with those physical characteristics of the fluid, such as viscosity, density, gell strength, etc., which determine the physical resistance to the passage of the blades therethrough.

Inasmuch as relative speed of rotation between the drill stem I3 and the tubular body 36 is a ,matter of maior importance as far asoperation of my improved drill is concerned, it is desirable to provide means for minimizing the friction between these parts. To this end, I have provided bearing means here illustrated in the form of a bushing 46 rigidly aillxed to the inside of body 36 and proportioned to establish bearing against a cooperative bearing face upon the outer surface of drill stem I3 or sub I2.

This arrangement minimizes the friction between the parts not onlybecause of the lvery natureof the bearing surfaces, but also because it operates to retain the parts in coaxial relation. Operation of the tool with the parts out of axial 'alignment would result in the development of relatively great pressure of one part against the other by centrifugal force; and the increased friction resulting therefrom would interiere seriously with the-establishment of the desired rotational differential. y

The bearing 46 is illustrated as being composed of rubber, but it will be understood, that other i bearing materials may be employed. An upper bearing 41 may also be employed and either or both of these bearings may be composed of rubber, as illustrated, or suitable soft metals such as bronze or the like in accordance with conventional practice.

It is also within the scope of the present invention to reverse the arrangement of parts of the bearing as in the modification oi' Figs. 4 and wherein the bearing 46' is rigid with the sub I2 and establishes bearing contact with the interior surface of the tubular body 36. This modication also is provided with an upperbearing 41 of suitable design and illustrated as made of metal.

However, the outstanding point of differentiation between the modification shown in Figs. 4 and 5 and that of Figs. 1 and 2 is that the drill of Figs. 4 and 5 is provided with a compression spring 66 interposed between the sub I2 on the mud can flow and thereby` reduce the tendency for the tool to ball up." This constructionlpossesses the added advantage of creating eddy curt rents around the blades which contribute to the development of the desired rotational differential.

of impeller blades is that they are substantially straight and parallel to the axis of the tool. Th'us vertical movement of the tool in the hole, or vertical movement of the fluid past the tool, has no effect upon the blades. Only by rotation of the tool in the fluid is the resistance of the blades to passage through the fluid made manifest.

Referring now to thatvmodiilcation of my iny vention which is illustrated in Figs. 8-11, the numeral II again designates a shank, provided at its upper end with suitable means I2 of attachment to the lower end of a conventional drill stem I3. An operating head I4 at the lower end of the shank Il provides convenient means of attachment for a bit I1. As before, the bit I1 may be provided with oriilces I8 whereby circulation fluid I9 forced downward through the bore of the drill stem I3 and the bore 2I` of the shank II can escape'into the hole being drilled adjacent the cutting edges 23 of the bit I'I. Such circulation of the fluid I9 may be effected as by any convenient means (not shown). Fluid I9 thus supplied to the bit I1 flows upwardly therefrom through the hole which has been drilled and into the sump, carrying with it the detritus which has been cut away from the formation being drilled.

In this form of my invention, the lower cam 28a instead of being fixed to the operating head I4 is mounted for free rotation upon the upper surface thereof about the lower end ofthe shank II. In cooperative engagement with the cam surface on the upper end of cam 28a is an upper cam 3Ia connected to the shank Il to be rotated thereby but for free axial movement with respect thereto, as by one or more feather keys 43. Reliance may be placed solely upon the weight of the upper cam 3Ia to urge it into engagement with the lower cam 28a, or a. spring 56 may be employed under compression between the upper cam 3Ia and the sub I2 in a manner similar` to j v thatshown in Fig. 5.

As stated, the lower cam 28a is free to rotate upon the shank II and in this modification of my invention, the tubular" body 36 is therefore rigidly attached to the lower cam instead of the upper one. The tubular body 36 is preferably of sufllcient length to enclose the compression spring 56 and the sub I2, the latter of which can be relied upon with convenience to act as a guide for the upper end of the tubular body permitting rotational movement thereof without any material radial movement. As before, the tubularbody 36 v is provided with a plurality of perforations 39 and carries a plurality of varies or blades 31' extending radially outwardly. fromthe body 36 but not so far as to permit them to-en-v gagel the wall 38 of the drilled hole. It is apparent therefore that the only medium engaged by the blades 31' during operation Aof the'tool is the circulation uid I9 and any material whichit carries.

blades 31 with the circulation uld I9.

of helical form; and the-pitch of these blades is in that direction which causes the blades, as they rotate, to impose a thrust upon the circulation fluid I9 in its direction of iiow. Inasmuch as the blades 31' are carried by the tubular body 36 which in turn is ailixed to the lower cam 28a, it is apparent that rotation of the lower cam will be retarded because of the engagement of the However, the tubular body 38 and its associated cam 28a, being free to 4rotate upon the shank II, are caused to rotate only through frictional engagement which occurs principally at the cam faces. This permits full advantage to be taken of the variation in the degree of resistance to movement of the vanes or blades 31' through the fluid in proportion to their speed. If the drilling operator desires that the drill bit rotate without any impact action, he should rotate the drill stem at such low speed that the resistance to rotation of the tubular body and its associated cam memberv is less than that of the frictional resistance between the two cams which urges the lower cam and tubular body to rotate. On the other hand, if drilling conditions are such that the development of percussive action is desirable in adator has merely to increase the speed of rotation of the drill stem until the resistance to rotation of the lower cam, which is developed by impingement of the circulation uid against the blades 3l', is greater than the frictional interengagement between the two cam faces. When these conditions obtain, the tubular body 36 will lag, i. e. will not rotate as fast as the drill stem, thus causing the lower cam 28a to rotate at a lower speed than th'e upper cam 3Ia.

Because of the sloping nature of the interengagins surfaces of the cams, the upper cam 3Ia will be lifted as relative rotation between the ,two cams occurs, compressing the spring 56 until tothedrillbit l'l.

Due to the fact that the helical biases 31' exert a thrust against the circulation fluid in the same direction as that in which the circulation fluid is iiowing, it is apparent that in this form of my invention, the operator will have to rotate his drill lat a relatively higher speed in or'der'to develop the frictional resistance to rotation of the blades which is necessary to overcome the friction at the camv surfaces. Figs. 12-15, h owever, show a modified form of construction wherein the direction of angularity of the helical blades 31' is opposite to that shown in Figs. 8-11 already described. In the modification of Figs. 12-15 the drill bit is intendedtooperate at relatively lower rotational speeds, since the blades 31' in this case exert a thrust against the circulation fluid in the direction opposite to that in which the fluid is flowing, with the result that they do not need to rotate as `fast in order to develop the same amount of resistance to rotation. It is apparent therefore: that the tool can easily be designed to have its critical speed at any predetermined value, i. e. by varying the angularity of the spiral blades, or in some cases by 'ity, the speed at which the drill develops perv cussive action can easily be determined.

The modification of Figs. 12-15 further differs y from that of Figs. 8-11 in that the tubular body 3Ib will be caused to rotate 'with respect to the lower cam 28; and the'splined driving connecdition to the rotary motion of the drill, the opertion between the tube 36 and the upper cam 3Ib will permit the upper cam to reciprocate axially upon the shank II thuspermitting the cams to override each other. `The collar 46 fixedly mounted in tubular body 35 is supported against collar I2 of shank I3 by spring 56. Thus, when tubular body 38 rotates slower than shank I3, cam 3Ib overrides cam 28, and oscillates axially on shank I3. Inasmuch as body 3B cannot osoillate,l

.cam 3Ib slides on keys 42 up and down in body 36 against and under the impress of spring 58. Key 42 -has the function -of rotating cam 3Ib with body 36 while at the same time permitting cam 3Ib to reciprocate with respect to body 36. The cams are urged toward each other as before by a suitable spring 56 with the result that as this overriding action occurs the cams will come together with considerable shock, thereby impartf ing sumcient impact to the drill to increase its drilling elcienoy materially. i

As stated, the impact-actuating means in each oase has suiiicient clearance to avoid all contact with any part of the walls or bottom of the drilled hole and is caused to operate solely by its engagement with the circulation fluid and material borne by that fluid. When the fluid-engaging means is of helical form, in addition to being operable by rotation .of the drill within the fluid. it is also responsive to movement of the iiuid itself in an axial direction.

The helical form of the blades causes them-to exert a thrust against the iiuid in an axial direction; and the extent or magnitudeof the thrust thus developed is readily subject to control, which in turn. facilitates the design of the drill to confine its critical speed between relatively narrow limits. If the direction of the thrust exerted by l the helical blades is the same as that in which the circulation iluid is owing, the drill must be operated at a higher rotational speed before the cams are caused to operate. On the other hand, if the blades be oppositely inclined then the impact action of the drill will commence While the drill is being rotated at a considerably lower speed. Furthermore, it is believed that the helical blades will be materially more efficient in developing the frictional resistance to rotation because of the eddy currents which they tend to set up in the circulation uid as a result of which adjacent particles of the fluid are forced to implnge against each other and thereby develop friction within the iiuid itself in addition to that which develops at the surfaces of the blades and the tubular body which carries them.

While the particular apparatus herein shown and described in detail is fully capable of attaining the objects and providing the advantages hereinbefore stated. it is to be understood that it is merely illustrative of the presently preferred embodiment of my invention, and that I do not actually reversing the direction of that angularmean to limit myself to the details of construction or design herein shown, other than as deiined in the appended claims.

I claim:

1. A combination rotary and impact drill'having impact means adapted to be operated by rotation of said drill in a fluid, comprising a rotatable shank, a bit mounted upon said shank, means for attaching said shank to a rotating means, a. body revolubly mounted upon said shank, means between said body and said shank for maintaining coaxial relation therebetween, cam means interposed between said lbody and said shank for imparting reciprocatory motion to said body with respect to said shank when rotation therebetween occurs, said cam means comprising a cam on said shank and a cam on said body, and means associated with said body extending into and engaging said iiuid to retard rotation of said body when said drill is rotated in said fluid whereby said body cam reciprocates and impacts upon said shank cam to deliver impact to said bit.

2. A combination rotary and impact drill comprising a shank, means for attaching said shank to a rotary drill stem, a body revolubly mounted on said shank, cams between said body and said shank, one of said cams being rigid with said body and the other of said cams being rigid with said shank, said body cam being adapted to impact upon said shank cam when rotation therebetween occurs, a tubular structure upon said body, bearing means between said tubular structure and said shank for maintaining coaxial alignment therebetween, and fluid-engaging means upon said tubular structure extending radially into said uid to resist rotation of said tubular structure within said numana thereby retard rotation of said body with respect to said shank.

3. A combination'rotary and impact drill comprising a shank, means for attaching said shank to a rotary drill stem, a body revolubly mounted on said shank, cams between said body and said shank, one of said cams being rigid with said body and the other of said cams being rigid with said shank, said body carn being adapted to impact upon said shank cam when rotation therebetween occurs, a tubular structure upon said body, and fluid-engaging means upon said tubular structure extending radially into said iiuid to resist rotation of said tubular structure within said fluid and thereby retard rotation of said body with respect to said shank.

l0 tary drill stem, impact means upon said shank GOmDrising a cam rotated .by said shank. and a free cam rotatable with respect thereto, said free cam being urged to rotate with said shank cam by virtue of frictional engagement between the faces of said two cams and said cams being adapted to impact when rotated with respect to each other, and duid-engaging means revolubly mounted on said shank and engaging said free cam comprising a. tubular structure and a helical lblade extending into engagement with said uid. said helical blade being adapted to urge adjacent fluid upwardly in the drilled hole, when rotated by said -free cam,

and to retard rotation of said free cam with respect to said shank whenv resistance lto rotation of said blade through said fluid becomes greater than friction between the faces of said two cams.

6. In a drill having impact means adapted to be operatedby rotation of said drill in a duid, a shank, means for attaching said shank to a rotary drill stem, impact means upon said shank comprising a cam rotated by said shank, and a free cam rotatable with respect thereto, said free cam being urged to rotate with said shank cam by virtue of frictional engagement between the faces of said two cams and said cams being adapted to impact when rotated with respect to each other, and duid-engaging means revolublymounted on said shank and engaging said free cam comprising a tubular structure and a helical blade extending into engagement with said iiuid, said helical blade being adapted to urge adjacent fluid downwardly in the ldrilled hole when rotated by said free cam, and to retard rotation of said free cam with respect to said shank when resistance to rotation of said blade through saidv iiuid becomesV greater than friction between the faces of said two cams.

7. In a, combination rotary and impact drill having impact -meansadapted to vbe operated by rotation of said drill in a fluid, a shank,means for attaching said shank-to a drill stem, a body revolubly mounted on said shank, a cam rigid `with said body, a second cam upon said body cam,

said second cambeing adapted to impact against said body cam when rotation therebetween occurs, coupling means between said second cam and said shank lwhereby said second cam reciprocates with respect to said shank -and rotates therewith, and fluid-engaging means associated with said .body and adapted to retard rotation -of said body with respect to said shank and comprising a tubular structure and duid-engagingelements extending radially from said tubular impact when rotated with respect to each other,

and fluid-engaging means revolubly mounted on said shank and engaging said free cam comprisving a tubular structure anda helical blade extend- 5. In a, drill having impact means adapted to y be operated by rotation of said drill in a fluid,

a shank, means for attaching said shank to a roimpact means between said'body and said shank structure into said iiuidand adapted to resist rotation therein whereby the rotation of said body-v is retardedwith respect to said shank and said second cam impacts upon said body cam.

8. A combination rotary and-impact drill having impact means adapted to be operated by rotation of said drill in a fluid, comprising a shank, means for attaching said shank to a rotary means, a body revolubly mounted on said shank,

comprising a cam rigid with said body and a, cam rigid with said shank, said body cam being adapted to impact upon said shank cam when rotation between saidl body and said shank occurs, andv duid-engaging means associated with said body and adapted to retard rotation of said body with respect to said shank comprising a tubular structure, coupling means between said tubular structure and said body whereby' said body may reciprocate axially with respect to said tubular structure and is rotated with said tubular structure,

amavis and duid-engaging elements extending radially from said ltubular structure into said fluid and adapted to resist rotationdn said uid and retard rotation of said body with respect to said shank.

9. A rotary impact drill for earth boring, which includes: a shank adapted to have a bit attached thereto; means `i'or attaching said shank to a rotary drillstem whereby said shank and bit can be rotated in a hole having drilling iluid therein; a driving cam mounted on said shank and rotatable therewith; a driven cammounted on said shank and adapted to be rotated by rotation of said driving cam, one o! said cams being reciprocable on said shank; and means rotatable with said driven cam extending into an engaging saiduid suillciently to retard rotation of said driven cam by engagement with said fluid to thereby cause said reciprocable cam to reciprocate and y produce an' impact on said shank, said fluid engaging means remaining rotatable with respect to the wall of said hole.

l0. A rotary impact drill for earth boring, which: includes: a shank adapted to have a bit attached thereto; means forI attaching said shank to a rotary drill stem wherebysaid shank and bit can be rotated in a hole having drilling fluid therein; a driving cam mounted on said shank and rotatable therewith; a driven cam mounted on said shank and adapted to be rotated by rotation of saiddriving cam, one of said cams being reciprocable on said shank; and a body rotatable with said driven cam provided with a radially extending blade of substantial size to sunlciently establish relative rotation between said cams and 12 l establish relative rotation between said cams and cause saidreciprocable cam to reciprocate and produce an impact on said shank, said body re;A maining rotatable with respect to the wall of said hole.

13. A rotary impact drill for earth boring, which includes: a shank adapted to have a bit attached thereto; means for attaching said shank to a rotary drill stem whereby said shank and bit can be rotated in a hole having drilling fluid therein; a driving cam mounted on said shank and rotatable therewith; a driven cam mounted on said shank and adapted to be rotated by rotation of said driving cam, one of said cams being reciprocable on said shank; and a body rotatable with said driven cam provided with a plurality of radially extending helical blades disposed at different angles and ofsuillcient size to materially retard rotation of said driven cam by substantial engagement with said fluid to thereby establish relative rotation between said cams and cause said reciprocable cam to reciprocate and produce retard rotation of said driven cam by'engagement with said duid to thereby establish relative rotation between said cams and cause said reciprocable cam to reciprocate and produce an impact on said shank, said body remaining rotatable with respect to the wall of said hole.

11. A rotary impact drill for earth boring, which includes: a shank adapted to have a bit attached thereto; means for attaching said shank to a rotary drill stem whereby said shank and bit can be rotated in a hole having drillingnuid therein; a driving cam mounted on said'shank and rotatable therewith; a driven cam mounted on said shank and adapted to be rotated by rotation of said driving cam, one: of said cams being reciprocable on said shank; and a body rotatable with said driven cam provided with a radially extending helical blade extending into and engaging said fluid sumciently to retard rotation of said driven cam by engagement with said fluid to thereby establish relative rotation between said cams and cause said reciprocable cam to reciprocate and produce an impact on said shank, said body remaining rotatable with respect to the wall of said hole.

12. A rotary impact drill for earth boring, which includes: a shank adapted to have a bit attached thereto; means for attaching said shank to a rotary drill stem whereby said shank and bit can`be rotated in a hole having drilling fluid therein; a driving cam mounted on said shank and rotatable therewith; a driven cam mounted an impact on said shank, said body remaining rotatable with respect to the wall oi said hole.

14. A rotary impact drill for earth boring, which includes: a shank adapted to have a bit attached thereto; means for attaching said shank to a rotary drill stem whereby said shank and bit can be rotated in a hole having drilling uid therein; a driving cam mounted on said shank and rotatable therewith; a driven cam mounted on said shank and adapted to be rotated by rotation of said driving cam, said driven cam being reciprocable on said shank; and means rotatable with said driven cam extending into and engaging said fluid sufliciently to retard rotation of said driven cam by engagement with said fluid to thereby establish relative rotation between said cams and cause said driven cam to reciprocate and produce an impact on said shank, said fluid engaging means remaining rotatable with respect to the wall of said hole.

15. A rotary .impact drill for earth boring, which includes: a shank adapted to have a bit attached thereto; means for attaching said shank to a rotary drill stem whereby said shank and bit on said shank and adapted to be rotated by rotation of said driving cam, one oi said cams being reciprocable on said shank; and a body rotatable can be rotated in a hole having drilling fluid therein; a driving cam mounted on said shank and rotatable therewith; a driven cam mounted on said shank and adapted to be rotated by rotation of said driving cam, said driving cam being reciprocable on said shank; and means rotatable with said driven cam extending into and engaging said fluid-suillciently to retard rotation of said driven cam by engagement with said iiuid to thereby establish relative rotation between said cams and cause said driving cam to reciprocate and produce an impact on said shank, said uid engaging means remaining rotatable with respect to the wall ci' said hole.

16. A rotary impact drill for earth boring which includes: a shank adapted to have a. bit attached thereto: means for attaching said shank to a rotary drill stem whereby said shank and bit can be rotated in a hole having drilling fluid to reciprocate said impact member when relative/JV rotation between it and said shank is established; and means rotatable with said impact member extending into and engaging said iluid sufciently t9 retard L'QtaiiiQll 01' said impact member by en'- bit can be rotated in a hole having drilling fluid therein; an impact member reciprocably mounted on said shank and rotatable therewith for delivery of impact thereto; means on said impact member cooperating with means rotatably `to a rotary drill stem whereby said shank and mounted on said shank for reciprocating said impact member when relative rotation between said shank and said rotatable member is established; and uid engaging means operable with said rotatable member adapted to retard rotation thereof solely by engagement with said fluid to thereby cause said relative rotation, said uid engaging means remaining rotatable with respect to the wall of said hole.

18. Apparatus for delivering impact to a drill bit being rotated in a hole having drilling uid therein, which includes: an impact member reciprocably mounted with respect to said bit and adapted to deliver impact thereto; means oper- `ably associated with said bit and impact member for reciprocating the latter; andactuatingmeans rotatablym'ountedwith respect to said bit but urged to rotate therewith, adapted vto actuate said reciprocating means when relative rotationisjestablished between said actuating means and saidv f bit, said actuating means having blade means extending into and engaging said fluid suiilciently to retard rotation of said actuating means with respect to said bit while permitting it to remain,

rotatable with respectto the wall of said hole.

19. Apparatus for delivering impact to a drill bit being rotated in a hole having drilling iiuidl` therein, which includes: an `impact member re-` ciprocably mounted with respect to said bit and adapted to deliver impact thereto; means associated with said bit and impact member for reciprocating the lattersaid means including `al member rotated with said bit. and a cooperating member' rotatable with respect to said bit but frictionally y urged to rotate therewith by said rst member; l

and iluid engaging blade means of extensive area connected to said rotatable member and vextending-into and engaging said fluid sufficiently lto retard rotation of said rotatable member solelyv in responseto the drag of said fluid on said blade -means', to thereby reciprocate said impact memaber, said iluid engaging means remaining rotatable with respect to the wall of said hole.

20. A rotary impact drill for earth boring which includes: a shank adapted to have a bit attached while said fluid drag means is rotating with respect to the wall of said hole.

21. A rotary impact drill for earth boring which mally urged to rotate by and with said shank; and\means responsive to the retardation of said uid engaging means due solely to the drag of 4 member while said body is rotating 14 said iiuid th'ereon for operating said impact means even though said iiuid engaging means is rotating with respect to the wall of said hole.A

22.In a drill having impact means adapted to be operated by rotation of said drill in a iluid, a shank, means for attaching a bitto said shank. means for attaching said shank to a rotary drill stem, impact means upon said shank comprising a cam rotated by said shank, and a free cam rotatable with respect-thereto, said free cam being urged to rotate with said shank cam by virtue lof frictional engagement between the faces of said two cams and said cams being adapted to impact when rotated with respect to each other, and lfluid-engaging means rotatably mounted on said shank and iixed to said free cam comprising a tubular structure and a blade xed thereto ex-` tending into engagement with said vuid, said blade being adapted to retard rotation of said free attached'thereto; means for attaching said shank l to arotary drill stem whereby said shank and bit l can be rotated in a holev having drilling iiuid therein; a tubular impact member reciprocably mounted on-said shank coaxially therewith; a pair of overriding cam members coaxially mount- -ed on said shank` for reciprocating said impact member, one oi' saidcams l'being rotatable with said shank, and the other being rotatable thereon but frictionally urged to rotate therewith; and a tubular body rotatably mounted on said shank and provided with blades extending into said iluid to engage the same and be suiiiciently retarded thereby to cause relative rotation between said cam members and reciprocation of said impact 'to the wall of said hole.

24. A rotary impact drill for earth boring which includes: a shank adapted to yhave a drill bit attached thereto; means for attaching said shank to a drill'stem for rotation in a hole having drilling fluid therein; la tubular body mounted coaxially on said shank and rotatable thereon; ar i 'blade on the outside of said body extending into s'aidK-uid and having a maximum radius of rota- -tion less than the radius of rotation of said bit and an' area su'iiicient to retard rotation of said body with respect to said shank due to the drag yof said fluid against-said blade becoming greater thanv the frictional urge tending to rotate said body with said shank; and impact means between said body and shank including complemental cam means, one part of which .is rotatable with said shank and theother part of which is rotatable with said body, said cam vparts being adapted to includes: .a shank adapted to have a bit attached thereto and to be rotated in a hole having drilling iiuid therein; impact means reciprocably mount-` ed on said shank; and fluid engaging means noroverride and actuate said impact means when said body is retarded by the engagement of said blade with said uid.

25. A combination rotary and impact drill com-` prising a shank adapted to have a bit attached thereto, means for attaching said shank to a rotary drill stem, a body revolubly mounted on said shank, cams between said body and said shank,

one of said cams being rotatable withsaid body and the other of said cams being rotatable with -said`shank, said body cam being adapted to impact upon said shank cam when rotation therewith respect lar structure extending'radially into said uid to resist rotation of said tubular structure within said duid and thereby retard rotation of said body with respect to said shank. .1

26. A combinationrotary and impact drill thereto, means for attaching said shank to a rotary drill stem, a body revolubly mounted on said shank, cams between said body and said shank, one oi' said cams being rotatable with said body and the other of said cams being rotatable with said shank, one oi said cams being adapted to impact on the other when rotation therebetween occurs, a tubular structure upon said body, and duid-engaging means upon said tubular structure extending radially into said iluid to resist rotation of said tubular structure; within said iluid and thereby retard rotation of said body with respect to said shank.

27. A combination rotary and impact drill having impact means adapted to be operated by ro- 'tatlon of said drill in a fluid, comprising a vrsa-- tatable shank adapted to have a bit attached thereto, means for attaching said shank to a rotating means, a body revolubly mounted upon said shank, cam means interposed between said body and said shank for imparting reciprocatory motion to said body with respect to said shank when rotation therebetween occurs, said cam means comprising acam on said shank and a cam on said body, and means associated 'with said body extending into and engaging said fluid to retard rotation of said body when said drill is rotated in said iiuid whereby said body cam reciprocates and impacts upon said shank cam to deliver impact to said bit.

28. In a drill having impact means adapted to be operated by rotation of said drill in a huid. a shank adapted to have a bit attached thereto,

means for attaching said shank to a lrotary drillstem, impact means upon said shank comprising a cam rotated by said shank and a free cam rotatable with respect thereto, said free cam being comprising a` shank adapted to have a blt attached iluld becomes greater than friction' between` the faces bf said two cams.

30. In a combination' rotary and -i'mpact drill having impact means adapted to be operated by rotation of said drill in a fluid, a shank adapted to have a bit attached thereto, means for attaching said shank to a drill stem, a body revolubly mounted on said shank. a cam rotatable with said body, a second camupon said body cam, one of said cams being reciprocable and adapted to impact on the other when rotation therebetween occurs, coupling means between said second cam and said shank whereby said second cam rotates with said shank, and fluid-engaging means associurged to rotate with said shank cam by virtue of irictional engagement between the faces of said two cams, said cams being adapted to impact when rotated with respect to each other, and

,uid-engaglng means revolubly mounted on said shank and ilxed to said free camv comprising a tubular structure and a blade extending into engagement with said fluid, said blade being adapted to retard rotation of said free cam with respect to said shank when resistance lto rotation of said blade through said iuid'becomes greater than friction between the faces 'of said two cams.

29. In a drill having impact means adapted to be operated 'by rotation of said drill in a iiuld, a shank adapted to have a bit attached thereto.

'means for attaching said shank to a rotary drill stem, impact means upon said shank comprising tubular structureand longitudinally extending i blade means having sections separated by spaces and extending into engagement with said iluid, said blade being adapted to retard rotation of said free cam with respect to said shank when resistance to rotation of said blade through said.

ated with said body and adapted to retard rotation of'said body with respect'to said shank and comprising a tubular structure and huid-engaging elements extending radially from said tubular structure into said iluid and adapted to resist rotation therein whereby the rotation of said body is retarded with respect to said shank and said cams are caused to impact, said body remaining rotatable with respect to the wall of said hole.

31. A rotary impact drill for earth boring. which'includes: a shank adapted to have al bit attached thereto; means for attaching said shank to a rotary drill stem whereby said shank and bit can be rotated in a hole having drilling iluid therein; a driving cam coaxially mounted on said shank and rotatable therewith; a driven c am coaxially mounted. on said shank and adapted to be rotated by said driving cam, one oi said cams being reciprocable on said shank and vadapted to impact upon the other of said cams; and means rotatable with said driven cam extending into said uid and adapted to suillciently retard rotation of said driven cam by engagement with said iluid to thereby establish relative rotation between said cams and cause said reciprocable cam to reciprocate and impact upon the other of said cams, said body remaining rotatable with respect to the wall of said hole.

32. A rotary impact drill for earth boring. which includes: a shankadapted to have a blt attached thereto; means for attaching said shank to a rotary drill stem whereby said shank and bit can be rotated in a hole having drilling uid therein: a driving cam-coaxially mounted on said shank and rotatable therewith; a free cam coaxially mounted on said shank and adapted to be rotated by said driving cam, one o! said cams being reciprocable on said shank; and means rotatable with said free cam in permanent engagement with the iluid -in said hole and adapted to suilieiently retard rotation thereof by engage#A ment solely with said fluid to thereby establish relative rotation between said cams and cause said reciprocable cam to reciprocate and produce an impact on said shank, without engagement with the wall of said hole.

33. A rotary impact drill for earth boring, which includes: a shank adapted to have a bit attached thereto; means for attaching said shank to a rotary'drill stem wherebysaid shank and bit can be rotated in a hole having drilling iluid therein; a driving cam coaxially mounted on said shank and rotatable therewith; a iree cam coaxially mounted on said shank and urged to rotate by said driving cam, one of said cams being reciprocable on said shank; and means rotatable'with said free cam of suillcient uidengaging area to offer resistance to rotation'of said free cam greater than the force urging it to rotate with said driving cam to the eby retard rotation thereof solely by engagemen with said 17 fluid to thereby establish relative rotation between said cams and cause said reciprocable cam to reciprocate and produce an impact on said shank, without engagement with the wall of said hole.

34. A rotary impact drill for earth boring, which includes: a shank adapted to have a bit attached thereto; means for attaching said shank to a rotary drill stem whereby said shank and bit can be rotated in a hole having drilling iluid therein; a driving cam coaxially mounted on said shank and rotatable therewith; a iree cam coaxially mounted on said shank and adapted to be rotated by said driving cam, one of said cams being reciprocable on said shank; and a body rotatable with said free cam provided with a radially extending blade of less radius than that of said hole adapted to materially retard rotation thereof by engagement with said fluid to 8 thereby establish relativeV rotation between said cams and cause said reciprocable cam to re-v eiprocate and produce an impact on said shank. while said body remains rotatable with respect to the wall of said hole.

. ROBERT E. BNYDER.

REFERENCES cr'rrtnv The following references are of record in the ille of this patent:

UNITED STATES PATENTS